Use "Taunt mode" to make enemies spawn without delay. This will allow you to quickly heal if needed.
Unfortunately, that only works for a few mobs. Once you've defeated a boss, it doesn't do anything, and if you go too high, then you're stuck waiting for your own respawn timer, which is far longer. (And you get no loot during taunt)
It's also frustrating how far back it feels like this update has pushed us. I was ALMOST to being able to equip 9 items at once, and now I'm stuck at 4 with no possible upgrades to raise it any. Right now, I feel like I can't equip anything worth using because the negatives on items are too strong and there's not enough slots to balance them anymore. Whether it's from the loss of relics or the loss of heirlooms (since I lost both). Whatever it is has made this section much more frustrating to play, and it was the part I actually enjoyed.
>(And you get no loot during taunt)
That's not true, you get bones at usual rate, only thing you are missing are monster parts. Plus if you reach boss during taunt - you will start getting monster part in-between "normal mobs".
You need to adjust to the new Horde mode, but it actually way better than old. Souls and trinket farm are nicer, you can get monster parts while level rushing, equipment is more meaningful (lets be honest here - having to wear 9 items is kill whole idea of limited slots)
I do agree, it makes the whole thing way more strategical to be able to climb the last few zones before the prestige reset, trying each time to grab the farthest possible droppable equipment. You can now switch loadouts to change strategy between farming, climbing and boss fight, something that I was almost never doing before because I could just equip everything I wanted